US3718765A — Communication system with provision for concealin…

Claim 1

Independent Claim 197 words

In telephone apparatus comprising a line, a speaker, a microphone, and a hybrid circuit connecting the speaker and microphone to each other and to said line for the transmission and receipt of signals and for the balancing of signals between said speaker and microphone, an improvement for interfering with the unauthorized interception of intelligence signals passing between said apparatus and another like apparatus, said improvement comprising a second speaker, a second microphone, and coupling means coupling the second microphone with the first microphone and the second speaker with the first speaker, said means selectively coupling intelligence signals from the second microphone to said first microphone for transmission via said line to said other apparatus and transmitting a control signal of predetermined frequency to said first microphone for transmission via said line to said other apparatus, said means including a noise generator responsive to a signal of said predetermined frequency received from said other apparatus to transmit a noise signal via the first microphone onto said line to conceal intelligence signals received from said other apparatus, intelligence signals and the control signal being selectively transmitted between said apparatuses for the selective transmission of intelligence and generation of noise.

Claim 2

Dependent Claim 197 words

In telephone apparatus comprising a line, a speaker, a microphone, and a hybrid circuit connecting the speaker and microphone to each other and to said line for the transmission and receipt of signals and for the balancing of signals between said speaker and microphone, an improvement for interfering with the unauthorized interception of intelligence signals passing between said apparatus and another like apparatus, said improvement comprising a second speaker, a second microphone, and coupling means coupling the second microphone with the first microphone and the second speaker with the first speaker, said means selectively coupling intelligence signals from the second microphone to said first microphone for transmission via said line to said other apparatus and transmitting a control signal of predetermined frequency to said first microphone for transmission via said line to said other apparatus, said means including a noise generator responsive to a signal of said predetermined frequency received from said other apparatus to transmit a noise signal via the first microphone onto said line to conceal intelligence signals received from said other apparatus, intelligence signals and the control signal being selectively transmitted between said apparatuses for the selective transmission of intelligence and generation of noise.

Claim 3

Dependent Claim 87 words

Apparatus as claimed in claim 1, wherein said means includes first and second generator means for generating first and second control signals one of which is the first control signal transmitted by said coupling means and first and second receiver means respectively adapted for receiving one of the control signals from said other apparatus, said generator means being coupled to the first said microphone, said receiver means being connected to the first said speaker, and cut-off means responsive to said receiver means to actuate said noise generator.

Claim 4

Dependent Claim 48 words

Apparatus as claimed in claim 2 comprising a mixer coupling said generator means and noise generator to the first said microphone, an amplifier coupling said second microphone to said mixer, a power supply, and first switch means coupling said power supply to said noise generator and generator means.

Claim 5

Dependent Claim 35 words

Apparatus as claimed in claim 3 comprising second switch means connecting said power supply selectively to one of the generator means and receiver means or to the other of the generator means and receiver means.

Claim 6

Dependent Claim 61 words

Apparatus as claimed in claim 4 comprising a handset supporting said second microphone and speaker, a switch actuating said power supply and operated upon displacement of said handset, said second switch means including means to switch the power supply from one generator means and receiver means to the other after the lapse of a predetermined time following displacement of said handset.

Claim 7

Dependent Claim 28 words

Apparatus as claimed in claim 5, wherein said first switch means is responsive to said amplifier to decouple the power supply from the noise generator and generator means.

Claim 8

Dependent Claim 30 words

Apparatus as claimed in claim 6, wherein said second switch means is coupled to one of the receiver means to receive a blocking signal from the latter to prevent switching.

Claim 9

Dependent Claim 36 words

Apparatus as claimed in claim 7 comprising speaker means coupling said mixer to said first microphone, microphone means coupled to said first speaker, and normally closed switch means coupling said microphone means to said second speaker.

Claim 10

Dependent Claim 72 words

Apparatus as claimed in claim 8 comprising a telephone cradle means, a second handset electrically coupled to said telephone cradle means and supporting said first microphone and speaker, a casing having openings to accommodate the secoNd handset and supporting the speaker means and microphone means adjacent the same, the first said means being supported in the casing and electrically coupled to the first said handset which is accommodated on said cradle means.

Claim 11

Dependent Claim 100 words

Apparatus as claimed in claim 7, wherein said second switch means comprises a power source coupled to the switch operated by the first said handset, first and second latch relays operated by respective of said receiver means, and including switch means for coupling said power source to said noise generator, and a time delay relay including an armature coupled between said noise generator and the switch means of one of the latch relays and a switch means coupling said power source selectively to one of the receiver and generator means or to the other of the receiver and generator means.

Claim 12

Dependent Claim 108 words

A telephone system comprising first and second telephone stations mutually coupled for the transmission of intelligence therebetween and each including speaker-microphone means, noise generator means coupled to the speaker-microphone means and control means coupled to the noise generator means and speaker-microphone means, the speaker-microphone means of one station being adapted to transmit control signals of a predetermined frequency from the associated control means to the control means of the other station which is thereby actuated to control the noise means of said other station to transmit noise signals through the speaker-microphone means of said other station to conceal intelligence being received by the latter from said one station.

Claim 13

Dependent Claim 108 words

A telephone system comprising first and second telephone stations mutually coupled for the transmission of intelligence therebetween and each including speaker-microphone means, noise generator means coupled to the speaker-microphone means and control means coupled to the noise generator means and speaker-microphone means, the speaker-microphone means of one station being adapted to transmit control signals of a predetermined frequency from the associated control means to the control means of the other station which is thereby actuated to control the noise means of said other station to transmit noise signals through the speaker-microphone means of said other station to conceal intelligence being received by the latter from said one station.

Claim 14

Dependent Claim 119 words

A telephone system comprising first and second telephone stations mutually coupled for the transmission of intelligence therebetween and each including speaker-microphone means, noise generator means coupled to the speaker-microphone means, control means coupled to the noise generator means and speaker-microphone means and including cut-off means coupled to the control means and speaker-microphone means, the speaker-microphone means of one station being adapted to transmit a control signal from the associated control means to the control means of the other station which is thereby actuated to control the cut-off means of said other station to disengage the associated speaker means and therefore prevent the noise signals being transmitted from said one station from reaching the speaker means of said other station.

Claim 15

Dependent Claim 119 words

A telephone system comprising first and second telephone stations mutually coupled for the transmission of intelligence therebetween and each including speaker-microphone means, noise generator means coupled to the speaker-microphone means, control means coupled to the noise generator means and speaker-microphone means and including cut-off means coupled to the control means and speaker-microphone means, the speaker-microphone means of one station being adapted to transmit a control signal from the associated control means to the control means of the other station which is thereby actuated to control the cut-off means of said other station to disengage the associated speaker means and therefore prevent the noise signals being transmitted from said one station from reaching the speaker means of said other station.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1976-02-27	1976-08-28	1977-02-27	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1980-02-27	1980-08-28	1981-02-27	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1984-02-27	1984-08-28	1985-02-27	$7700.00	Window Closed / Lapsed

Communication system with provision for concealing intelligence signals with noise signals

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